Low-Power eCompass Modules Used in Xiaomi Handsets

SAN FRANCISCO — STMicroelectronics recently introduced its LSM303D accelerometer and magnetometer combo module to Chinese smartphone leader Xiaomi (Mi1S), known as the country’s answer to Apple.

“Our MEMS technology continues to raise the bar in every quarter: power consumption, performance, price, and physical size,” said Benedetto Vigna, executive vice president and general manager of the analog, MEMS, and sensors group at STMicroelectronics, in a statement. “This, in turn, allows dynamic new companies such as Xiaomi to raise the bar in their own markets.”

STM developed its family of eCompasses around the principal of magneto resistance (MR) -- where a material changes the value of electrical resistance when an external magnetic field is applied -- to decrease power consumption. Devices, including the recently released LSM303, use MR “matching or exceeding the performance of competitive devices in module size, full-scale resolution and noise,” the release stated.

The LSM303 accurately measures the direction and magnitude of external magnetic fields, while the module’s accelerometer compensates for tilt to ensure an accurate compass heading when portable devices are inclined. LSM303 combines a 3-axis magnetic-field sensor and a 3-axis accelerometer in a single tiny 2x2x1 mm module.

“This is a peripheral piece that… could be useful in location-based services, if you were walking around in a mall or were driving and wanted to know where you were,” an ST spokesman told EE Times.

In November, the LSM303C, a member of the same family of devices, was selected as device of the year by the MEMS Industry Group for its improved power consumption and size.

“In smartphones and other mobile devices, every milliwatt matters,” said Vigna. “The ST device meets minimal size constraints and allows significant reductions in power consumption without compromising performance in other areas. These advantages help manufacturers to provide mobile devices that meet customer expectations while minimizing the drain on the world’s resources.”

The LSM303D is already shipping, and ST plans to introduce new models shortly.